Cancer is a class of diseases in which a group of cells display uncontrolled growth, invasion and sometimes metastasis. These three malignant properties of cancers differentiate them from benign tumors, which are self-limited, do not invade or metastasize. Among men, the three most commonly diagnosed cancers are prostate, lung and colorectal cancer in developed countries. Particularly prostate cancer is the most common malignancy in European males. In 2002 in Europe, an estimated 225,000 men were newly diagnosed with prostate cancer and about 83,000 died from this disease.
Certain phosphodiesterases have been associated with cancer development. For instance, phosphodiesterase PDE7 has been shown to be linked to chronic lymphocytic leukemia (Zhang L et al., PNAS, 2008, 105(49): 19532-7). Yet, for many cancer types or cancer progression forms there is no adequate marker molecule available.
Prostate cancer, for example, is traditionally diagnosed via the serum level of prostate-specific antigen (PSA). However, PSA is not prostate cancer-specific and can be raised in other circumstances, leading to a large number of false-positives (cancer is not found in around 70% of men with raised PSA levels who undergo biopsy). Furthermore, there will be an unpredictable number of false-negatives who later develop prostate cancer in the presence of a “normal” PSA test.
Therefore, there is a need for the provision of a new and effective, alternative diagnosis perspective for the detection, monitoring and prognostication of prostate cancer.